HydraMaster Boxxer 421, Owner'S Manual

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HydraMaster Corporation
Page 6-4: High Pressure Pump
Boxxer 421
To avoid damage to either plunger or seal, keep the manifold properly
aligned with the ceramic plungers when removing it.
4. Remove the seal retainer from the manifold and inspect for wear.
5. Examine the ceramic plunger for cracks or scoring (refer to Servicing the
Plungers for replacement).
Servicing the Low Pressure Seals and High Pressure Seals
(See Figure 6-1)
1. Remove the low pressure seal from the seal retainer using a 90 degree pick
tool.
2. Remove the high pressure seal from the manifold
3. Inspect the low pressure seal and high pressure seal for wear and replace
if necessary.
4. Reinstall the low pressure seal into the seal retainers with the garter
spring down.
5. Reinstall the high pressure seal:
a) Lubricate the seal chamber in the manifold.
b) Carefully square the high pressure seal into position by hand, with the
grooved side down (metal back facing out).
c) Examine the seal retainer’s O-ring and replace if worn. Lubricate the new
O-ring before installing.
d) Press the seal retainers into the manifold until completely seated.
Servicing the Plungers
1. Using a hex tool, loosen the plunger retainer about three to four turns. Push
the back to separate it from the retainer and finish unthreading the plunger
retainer by hand.
2. Unthread the plunger retainer with sealing washer.
3. Remove the ceramic plunger, keyhole washer and barrier slinger from the
plunger rod.